1. Field of the Invention
The present invention relates to a solid-state imaging apparatus and a method for driving solid-state imaging apparatus.
2. Description of the Related Art
A CMOS image sensor including an analog-to-digital (AD) conversion circuit has been used in an image input device such as a digital camera. The AD conversion circuit compares an image signal with a reference signal to obtain digital data. As a reference signal, a ramp signal having a time-changing signal level and generated by controlling a charging current for a capacitor element is described in Japanese Patent Application Laid-Open No. 2009-33305.